ChartDirector 6.0 (Ruby Edition)

Contour Color Scale


      

This example demonstrates using various coloring for the ContourLayer.

The ChartDirector supports two ways to configure the colors for a contour.

This example includes 4 charts to demonstrate both of the above methods.

Source Code Listing

[Ruby On Rails Version - Controller] app/controllers/contourcolor_controller.rb
require("chartdirector")

class ContourcolorController < ApplicationController

    def index()
        @title = "Contour Color Scale"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 4
        render :template => "templates/chartview"
    end

    #
    # Render and deliver the chart
    #
    def getchart()
        # This script can draw different charts depending on the chartIndex
        chartIndex = (params["img"]).to_i

        # The x and y coordinates of the grid
        dataX = [-4, -3, -2, -1, 0, 1, 2, 3, 4]
        dataY = [-4, -3, -2, -1, 0, 1, 2, 3, 4]

        # Use random numbers for the z values on the XY grid
        r = ChartDirector::RanSeries.new(99)
        dataZ = r.get2DSeries(dataX.length, dataY.length, -0.9, 0.9)

        # Create a XYChart object of size 420 x 360 pixels
        c = ChartDirector::XYChart.new(420, 360)

        # Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent grey
        # (0xdd000000) horizontal and vertical grid lines
        c.setPlotArea(30, 25, 300, 300, -1, -1, -1, 0xdd000000, -1)

        # Set the x-axis and y-axis scale
        c.xAxis().setLinearScale(-4, 4, 1)
        c.yAxis().setLinearScale(-4, 4, 1)

        # Add a contour layer using the given data
        layer = c.addContourLayer(dataX, dataY, dataZ)

        # Move the grid lines in front of the contour layer
        c.getPlotArea().moveGridBefore(layer)

        # Add a color axis (the legend) in which the top left corner is anchored at (350, 25). Set
        # the length to 400 300 and the labels on the right side.
        cAxis = layer.setColorAxis(350, 25, ChartDirector::TopLeft, 300, ChartDirector::Right)

        if chartIndex == 1
            # Speicify a color gradient as a list of colors, and use it in the color axis.
            colorGradient = [0x0044cc, 0xffffff, 0x00aa00]
            cAxis.setColorGradient(false, colorGradient)
        elsif chartIndex == 2
            # Specify the color scale to use in the color axis
            colorScale = [-1.0, 0x1a9850, -0.75, 0x66bd63, -0.5, 0xa6d96a, -0.25, 0xd9ef8b, 0,
                0xfee08b, 0.25, 0xfdae61, 0.5, 0xf46d43, 0.75, 0xd73027, 1]
            cAxis.setColorScale(colorScale)
        elsif chartIndex == 3
            # Specify the color scale to use in the color axis. Also specify an underflow color
            # 0x66ccff (blue) for regions that fall below the lower axis limit.
            colorScale = [0, 0xffff99, 0.2, 0x80cdc1, 0.4, 0x35978f, 0.6, 0x01665e, 0.8, 0x003c30, 1
                ]
            cAxis.setColorScale(colorScale, 0x66ccff)
        end

        # Output the chart
        send_data(c.makeChart2(ChartDirector::PNG), :type => "image/png", :disposition => "inline")

    end

end

[Ruby On Rails Version - View] app/views/templates/chartview.html.erb
<html>
<body style="margin:5px 0px 0px 5px">

<!-- Title -->
<div style="font-size:18pt; font-family:verdana; font-weight:bold">
    <%= @title %>
</div>
<hr style="border:solid 1px #000080" />

<!-- Source Code Listing Link -->
<div style="font-size:9pt; font-family:verdana; margin-bottom:1.5em">
    <%= link_to "Source Code Listing", 
        :controller => "cddemo", :action => "viewsource",
        :ctrl_file => @ctrl_file, :view_file => File.expand_path(__FILE__) %>
</div>

<!-- Create one or more IMG tags to display the demo chart(s) -->
<% 0.upto(@noOfCharts - 1) do |i| %>
    <img src="<%= url_for(:action => "getchart", :img => i) %>">
<% end %>

</body>
</html>

[Command Line Version] rubydemo/contourcolor.rb
#!/usr/bin/env ruby
require("chartdirector")

def createChart(chartIndex)

    # The x and y coordinates of the grid
    dataX = [-4, -3, -2, -1, 0, 1, 2, 3, 4]
    dataY = [-4, -3, -2, -1, 0, 1, 2, 3, 4]

    # Use random numbers for the z values on the XY grid
    r = ChartDirector::RanSeries.new(99)
    dataZ = r.get2DSeries(dataX.length, dataY.length, -0.9, 0.9)

    # Create a XYChart object of size 420 x 360 pixels
    c = ChartDirector::XYChart.new(420, 360)

    # Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent grey
    # (0xdd000000) horizontal and vertical grid lines
    c.setPlotArea(30, 25, 300, 300, -1, -1, -1, 0xdd000000, -1)

    # Set the x-axis and y-axis scale
    c.xAxis().setLinearScale(-4, 4, 1)
    c.yAxis().setLinearScale(-4, 4, 1)

    # Add a contour layer using the given data
    layer = c.addContourLayer(dataX, dataY, dataZ)

    # Move the grid lines in front of the contour layer
    c.getPlotArea().moveGridBefore(layer)

    # Add a color axis (the legend) in which the top left corner is anchored at (350, 25). Set the
    # length to 400 300 and the labels on the right side.
    cAxis = layer.setColorAxis(350, 25, ChartDirector::TopLeft, 300, ChartDirector::Right)

    if chartIndex == 1
        # Speicify a color gradient as a list of colors, and use it in the color axis.
        colorGradient = [0x0044cc, 0xffffff, 0x00aa00]
        cAxis.setColorGradient(false, colorGradient)
    elsif chartIndex == 2
        # Specify the color scale to use in the color axis
        colorScale = [-1.0, 0x1a9850, -0.75, 0x66bd63, -0.5, 0xa6d96a, -0.25, 0xd9ef8b, 0, 0xfee08b,
            0.25, 0xfdae61, 0.5, 0xf46d43, 0.75, 0xd73027, 1]
        cAxis.setColorScale(colorScale)
    elsif chartIndex == 3
        # Specify the color scale to use in the color axis. Also specify an underflow color 0x66ccff
        # (blue) for regions that fall below the lower axis limit.
        colorScale = [0, 0xffff99, 0.2, 0x80cdc1, 0.4, 0x35978f, 0.6, 0x01665e, 0.8, 0x003c30, 1]
        cAxis.setColorScale(colorScale, 0x66ccff)
    end

    # Output the chart
    c.makeChart("contourcolor%s.png" % chartIndex)
end

createChart(0)
createChart(1)
createChart(2)
createChart(3)